Walmart has not earned that benefit of the doubt. Given that it is Walmart, the default is to assume that it will be exploitative until proven otherwise.
I've only heard good things about Costco. I wouldn't give Costco the benefit of the doubt. Every company (except nonprofits) exists to accrue profit. There's no other factor. They do not have any interest in mind than profit. I definitely assume the worst from Walmart.
